Air-operated tool

ABSTRACT

The device is an air-operated tool, particularly of the type used for rubbing, sanding or filing, that is, having a reciprocatory motion. The tool embodies a single double-ended piston in a bore, with a rack positioned between the ends of the piston. A reciprocatable shoe carries a second rack and a pinion gear is mounted between the two racks on a transverse axis the piston and shoe reciprocating in opposite directions. A rotarytype valve controls the admission to, and exhaust air from, the opposite ends of the piston while reciprocation is imparted to the shoe. The mass of the piston is balanced with respect to the shoe whereby vibration of the tool during operation is reduced to a minimum.

United States Patent 1.953.534 4/1934 Everett (cursory), 35 319 13952 225129559923521 921136;173/(1fi uired); 5 1/1 70.3 (Cursory) References Cited UNITED STATES PATENTS Primary Examiner- Paul E. Maslousky Attornev-Herzig and Walsh 1 v ABSTRACT: The device is an air-operated tool, particularly ofthe type used for rubbing. sanding or filing. that is, having a reciprocatory motion. The tool embodies a single doubleended piston in a bore. with a rack positioned between the ends of the piston. A reciprocatable shoe carries a second rack and a pinion gear is mounted between the two racks on a transverse axis the piston and shoe reciprocating in opposite directions. A rotary-type valve controls the admission to. and exhaust air from, the opposite ends of the piston while reciprocation is imparted to the shoe. The mass of the piston is balanced with respect to the shoe whereby vibration of the tool during operation is reduced to a minimum.

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[ t l I I I f0 .12 0 9432112 90 a 76 w The invention is an air-operated tool ofthe type particularly adapted for sanding, rubbing or filing operations and the like.

The tool is held manually while operating, the reciprocatory motion being imparted to a shoe carried by the tool by means ofair supplied under suitable pressure to the tool.

Various types of mechanisms have been known in the prior art adapted for use in this type of tool for imparting reciprocatory motion to a shoe. It is characteristic of the design and construction of tools of this type that it is desired that the operating parts be simple, sturdy, and dependable and easily maintainable. while at the same time being simple in construction. It is further desired that the operating parts be compact and that they do not occupy any more physical space than necessary. i I

It is also desired that the body of the tool be subjected to minimum vibration while in operation.

It is the primary object of this invention to provide airoperated driving means for a tool.of the type described and capable of meeting all of the aforesaid. characteristic requirements in an optimum way.

In a preferred form of the invention the reciprocating shoe is driven by way of racks with apinion gear on a transverse shaft mounted between them. That is, the pinion gear is in a vertical position. A single doubleended piston is provided with a rack extending between the ends of the piston in a position to engage the pinion which drives the rack carried by the reciprocating shoe. Valve means, preferably in the form of a vertical rotary valve, is providedin order to alternately admit air to opposite ends of the piston'and to exhaust air therefrom.

It is a particular feature ofthe invention that a single driving pinion is used, cooperating with the racks in a position between the opposite ends of the double-ended piston which operates in a common bore in the body of the tool. It has been found that a simplified construction ofthis type is very effective for the purposes desired, is compact, and simple in construction, and adapts itself very well to the purposes'intended.

Significantly in the invention a single double-ended piston is used which drives a single shoe, thepiston and shoes moving in opposite directions. An extremely significant aspect of the invention is that the mass or weight ofthe double-ended piston is balanced against the mass or weight of the reciprocatable shoe whereby the purpose is achieved of minimizing the vibrationof the tool. In this manner important objects of the invention are accomplished. Simplicity and economy of parts is realized because there is but a single double-ended piston and shoe driven thereby. It has been commonplace and conventional in the prior art in tools of this type to have a pair of pistons which are alike and a pair ofshoes which are alike and the pistons and shoes symmetrically, arranged with the mass of one piston and shoe balanced against an identical piston and shoe moving in opposite directions. Balancing is, of course, easy in such a symmetrical arrangement, but, of course, the duplicate pistons and shoes are present which adds to the weight, bulkiness. costs and maintenance aspects. In the.

herein invention by balancing the. mass of the single piston against the shoe the vibration is minimized although the tool only has the one piston and shoe. The elimination or minimization of vibration is, of course, extremely important since if the tool vibrates appreciably while in use it has very tion;

Another object of the invention resides in the particular positioning of the piston and itsv bore whereby to realize desirable results in the overall operation.

In the preferred form of the invention, the rotary type valve is operated by a second pinion rotating about a vertical axis and a further rack carried by the reciprocating shoe. Further objects of the invention reside in .the' attainment in the manner stated of the characteristics of simplicity and compactness of construction, accompanied by effectiveness of operation and service and ease of maintainability.

Further objects and additionaladvantages of the invention will become apparent from the following detailed description and annexed drawings, wherein: V

FIG. 1 is a view partly in section of one form of the inven- 7 I FIG. 2 is a sectional view taken along the line 2-2 of FIG. 1; FIG. 3 is a sectional view taken along the line 3-3 of FIG. 1; FIG. 4 is an exploded perspective view ofthe valve means; FIG. 5 is a sectional view taken-along the line 55 of FIG. I; FIG. 6 is a view partly in section ofa preferred form of the invention; 5

FIG. 7 is an exploded perspective view ofthe valve means of the form ofthe invention shown in FIG. 6;

FIG. 8 is a sectional view taken along the line 8-8 of FIG. 6;

FIG. 9 is a sectional view taken along the line 9-9 of FIG. 6.

Referring now more in detail to the various figures of the drawings: t

Numeral l0 designates the body of the tool which may be made of any suitable material and may be fabricated by casting or other suitable processes.

FIG. 5 shows the cross-sectional shape of the body of the tool.

Numeral 12 designates the rear part of the body ofthe tool. which may be made as a separate section and'attached to the body by any suitable means.

Numeral 41 designates the handle of the tool, which is hollow, as shown, and which is shaped to have its forward part attached to the body 10 and its rear part attached to the rear section 12 ofthe tool. 7 v

Numeral l6 designates a control handle or lever which extends through an opening 18 in the handle l4.and which is pivoted at 22. The member 16 is in the form of a bellcrank lever, having a lever part 24, to which is pivotally attached a the form ofa knob attached to the body 10 by being threaded into it.

At the bottom of the tool is a reciprocatable shoe 32 which i has cutouts at its lower outside edges, as designated at 34 and 36 in FIG. 5. The shoe is held in position by sideplates 40 and 42, which have inwardly extending flanges as shown at 44 and 46, which engage in' the undercuts34 and 36 at the side edges of the shoe 32 to hold it in position .while allowing it to reciprocate. 1

Attached to the shoe 32 may be any suitable type of tool, such as a file, as shown at 50, or the tool may be a rubbing or sanding tool. 1 j

The sideplates 40 and 42 may be held, in position by screws, such as shown at 52.

The driving mechanism of the tool will next be described.

Within the body 10 is a longitudinal .bore 56 and movable in this bore are pistons or piston ends 60 and 62, having a construction as shown, embodying angular grooves shown at 64 and 66, between the end surfaces .of the' pistons.

Positioned betweenthe pistons 60 and 62 is a rack bar member 70, having teeth on its underside, and this rack meshes with a pinion gear 72 The pinion gear 72 is mounted on a transverse shaft 74 that is journaled in bores in the side parts of the body at 10. The lower part. of the pinion gear 72 is positioned in or extends through an opening 76 in the lower part of the body 10, so that it can mesh with rack 78 carried by the shoe 32.

As may be seen, the pinion 72 is partly within the bore 56in a position between the pistons or ends of the double-ended piston and extends through the opening 76 so as to mesh with the rack 78.

In the body are additional elongated bores 82 and 84 positioned above the bore 56, as may be seen, and also the bore 90 at the end of bore 56. See FIG. 1.

Next will be described the valving mechanism that controls the operation of the driving means for the reciprocatable shoe.

Numeral 94 designates a vertical bore in the body 10, which can communicate with the bore 56 through the bore 90. Positioned in the bore 94 is cylindrical spool or sleeve 100 as may be seen in FIG. 4 which forms a part of the rotary valve mechanism. The sleeve 100 has a bore 102 and in one side there is provided an angular or arcuate cutout 104, having an angular extent as shown ofsomewhat less than 180.

In the opposite side of the spool or sleeve 100 is a similar arcuate cutout 106 of a similar angular extent.

Numeral 110 designates a rotary cylindrical valve member that fits into the bore 102 in the member 100. The member 100 has a top flange 112 which engages on the top of the spool or sleeve 100. It has an extending upper part 114 of smaller diameter, in the side of which is an axial rectangular slot 116, as shown. In the opposite side of the body of the member 100 is a similar axial rectangular slot 118. These slots within' the member 110 are separated by a septum, as shown at 122 in FIG. 1, providing for a flow of air within the rotary valve as will be described presently.

The member 110 has a 180 cutaway at the bottom end, as designated at 126.

Numeral 130 designates the drive member for the rotary valve means. It comprises a tubular member as shown, having a bore 132, and at the lower end it carries spur or pinion gear 134. At the upper end it has a 180 cutaway 136 which is complementary to the cutaway 126 at the bottom of member 110. The barrel of the drive member 130 fits into the lower end of the bore 102 of the spool or sleeve 100 and the member 110 fits into the upper end of the bore 102, so that these parts come into a position as shown in FIG. 1 just below the threaded bore 138 in the body 10, which can be closed by a screwplug.

Section 12 of the body 10 has in it a vertical bore 140, in which is a ring member 142 having a bore 144, which forms a valve seat for a ball valve 148 which is biased against the valve seat by a coil spring 152. The lower end of the bore 40 is closed by a screwplug 154. The upper end of bore 140 is closed by a similar screwplug 156, through which extends the operating stem 26 which has a small extending stem 160 that can open the ball valve 148 by unseating it.

In section 12 is a bore 162 to which is attached a suitable fitting 164 for connection to a source of air pressure through line 166. The section 12 also has a bore 170 that aligns with the bore 82in the body 10.

It will be observed, of course, that the double-ended piston 60-62 reciprocates in a direction oppositely to the reciprocation of the rack 78 andshoe 50. The pinion gear 72 is fixed. The mass or weight of the double-ended piston is balanced against the weight of the shoe and the rack 78. The result of this is that vibration of the body of the tool as a whole resulting from the reciprocation of the parts is minimized or eliminated. This is an important result for reasons explained in the foregoing. As may be seen this is accomplished in a tool having only the one double-ended piston and rack and shoe driven thereby In the form of the invention shown the double-ended piston is positioned over the shoe at one end thereof adjacent one end of the tool and the valve is ahead of the double-ended piston. Other arrangements are possible as described .h t na t r.

Theoperation of the tool will next be described. The operation is illustrated in FIGS. 2 and 3, which illustrate the positions of the rotary valve means.

The tool is grasped by the handles 14 and 30 and the operator can push upwardly on the control lever 16 to open or unseat the ball valve member 148 in the section 12. This admits air under pressure from the line 166 through the bores 170 and 82 to the rotary valve. Pressure is applied first to one of the pistons 60 and 62 and then to the other, the pressure being exhausted from that piston opposite from the one to which the pressure is being applied. FIG. 1 illustrates the flow of pressure to the piston 60.

The air moves from bore 82 into the slot 116, and then downwardly through the valve member 110 to the bore and into the chamber at the left end of piston 60 for driving the piston assembly to the right. This flow is illustrated in FIG. 3. At this time air is exhausted from the chamber opposite the end of piston 62. This takes place through the cutout or cavity 171 in the section 12, through-the bore 84 into the angular opening 106 in the valve body 100, and then downwardly through the slot 118 and into the bore 132 of the drive member 130, through which. t he air is exhausted.

The piston assembly and rack 70 are driven to the right looking at FIG. 2, rotating pinion gear 72 in a clockwise direction, and thus driving the rack 78 and shoe 32 to the left. When this happens the rack 169 is driven to the left along with the shoe 32, and it rotates the pinion gear 134 rotating the valve member in a counterclockwise direction looking at FIGS. 2 and 3. This rotates the spool or sleeve member 100 from the position of FIG. 3 through substantially 180 from the position shown in FIG. 3. The vertical slot 116 is now brought into position to communicate with the arcuate cutout 106, in the barrel 100 which communicates with the bore 84, allowing air under pressure to be delivered through the cutout or cavity to the end of piston 62.

As may be observed, air from the bore 82 can pass around the extending part 114 at the end ofthe valve member 110, so as to enter the channel 116 in any position ofthe member 110. At this time the air is exhausted from the chamber at the end of piston 60 through the bore 90, the cutout 104 into the vertical channel 118, and thence through the bore 132 to exhaust. In this manner, whenever the valve 148 is unseated air under pressure is applied to the mechanism which reciprocates the shoe 32 in response to the movements of the rotary valve as driven by the rack 169 and pinion 134. The operation is smooth and positive with vibration minimized.

FIGS. 6, 7, 8 and 9 show a modified form of tool which is different primarily in respect to the positioning of the doubleended piston. In this form of the invention the double-ended piston is positioned at the center part of the body of the tool over the middle of the reciprocating shoe This is a preferred manner of positioning the double-ended piston. All parts in FIGS. 6, 7, 8 and 9 that are the same as corresponding parts in the previous embodiment are identified by the same reference characters and, therefore, the description need not be re peated. With respect to parts in FIGS. 6, 7, 8 and 9 that are modified but otherwise correspond to a part in the previous embodiment such parts are identified by similar reference characters primed.

In the modification of FIGS. 6, 7, 8 and 9 the rotary valve is positioned to the rear of the double-ended piston although it could have other positions. The conduits leading to theopposite ends of the double-ended piston are identified by the numerals 84' and 90. I

The rotary valve is shown more in detail in FIGS. 7 and 8. The rotary valve 110' operates within the cylinder or spool 100 which is'received in the vertical bore 94 in the body 10' of the tool. The member 110 has a top flange 112 which engages on the top of the spool or sleeve 100' which has a bore 102. It has an extending upper part 114' of smaller diameter. The member 110 has diametrically. disposed axial slots having curved inner surfaces as designated at 116' and 118'. These slots within the member 110 are separated by a septum as designated at 122'.

The member 110 has a transverse diametral slot 113 at the bottom thereof.

Spool member 100 has a bore 102' and in one side there is provided an angular or arcuate slot or cutout 104' having an angular extent of somewhat less than In which opposite of the spool 100 is a similar arcuate slot or cutout 106' of a similar arcuate extent.

Numeral 130 designates the drive member for the rotary valve means. It comprises a tubular member as shown having a bore 132' and at the lower end it carried a spur or pinion gear 134' which is driven by the rack 169. At the upper end it has diametrically opposed axial lugs I25 and 127 which fit into the slot 113' in the member 110' for rotating it in the bore 102. The barrel of the drive member 130' fits into the bore 102 in the spool 100' and the member 110' fits into the bore 102 also as may be seen in the FIGS. with the extending part 114' exposed to the channel 82' as shown.

The operation ofthe tool of FIGS. 6, 7, 8 and 9 will next be described. The operation is illustrated in FIGS. 7 and 9 which illustrate the rotary valve means and its operation.

The tool is grasped as described in connection with the previous embodiment and the pressure is controlled by the handle 16 as already described. Pressure is admitted first to one and then the other of the double-ended piston, pressure being exhausted from one end while applied to the other.

The air moves from bore 82 in the groove or slot 116' in one position of the valve and then through the arcuate slot 104' into the channel 84' to the bore opposite the end of the piston 60. At this time pressure at the other end of the piston exhausts through the channel 90' to the'arcuate slot 106 and downwardly through the bore I32 in the member 130' to ex haust through the radial port 135 in the gear 134'. Piston 60 moves to the right driving shoe 50 and racks 78 and 169 to the left. This rotates valve member 110 into its opposite position wherein air is exhausted from the chamber at the end of position 60, through channel 84', cutout 100', slot 118' and bore 102' to port 135. Pressure is now admitted through slot 116' from bore 82' to cutout 104' and channel 90' to the chamber at the end of piston 62 for moving it in the opposite direction.

From the foregoing those skilled in the art will understand and appreciate the nature and construction of the invention and the manner in which it achieves and realizes all of the objects set forth in the foregoing and the advantages, as well as the many advantages that are apparent from the detailed description.

The foregoing disclosure is representative of preferred forms of the invention and is to be interpreted in an illustrative rather than a limiting sense, the invention to be accorded the full scope of the claims appended hereto;

Iclaim:

l. A manually held fluid-actuated tool comprising a body defining a cylinder bore, piston means comprising a single double-ended piston reciprocatable in the bore, valve means having communication with said bore and means whereby the valve means are operated in response to the reciprocation of the piston means to control admission and release of fluid pressure with respect to the bore for actuating the piston means, rack means carried by the piston means, a reciprocatable shoe, a rack carried by said reciprocatable shoe, and a driving pinion gear interposed between said racks whereby the piston means and shoe are driven in opposite directions, the mass of the reciprocatable piston means being balanced with respect to the mass of the reciprocatable shoe whereby vibration of the device is reduced to a minimum.

2. A tool as in claim 1 wherein said first rack is positioned between opposite ends of the piston means.

3. A tool as in claim 1 having the single-double-ended piston positioned over the reciprocatable'shoe.

4. A tool as in claim 3 wherein the piston means has a central position between the ends of the reciprocatable shoe.

5. A toolas in claim 1 including a further rack driven by said piston means, said valve means being a rotary-type valve and a pinion gear driven by said further rack operating said rotary valve means.

6. A tool as in claim 5 wherein the axis of the rotary valve 

1. A manually held fluid-actuated tool comprising a body defining a cylinder bore, piston means comprising a single double-ended piston reciprocatable in the bore, valve means having communication with said bore and means whereby the valve means are operated in response to the reciprocation of the piston means to control admission and release of fluid pressure with respect to the bore for actuating the piston means, rack means carried by the piston means, a reciprocatable shoe, a rack carried by said reciprocatable shoe, and a driving pinion gear interposed between said racks whereby the piston means and shoe are driven in opposite directions, the mass of the reciprocatable piston means being balanced with respect to the mass of the reciprocatable shoe whereby vibration of the device is reduced to a minimum.
 2. A tool as in claim 1 wherein said first rack is positioned between opposite ends of the piston means.
 3. A tool as in claim 1 having the single double-ended piston positioned over the reciprocatable shoe.
 4. A tool as in claim 3 wherein the piston means has a central position between the ends of the reciprocatable shoe.
 5. A tool as in claim 1 including a further rack driven by said piston means, said valve means being a rotary-type valve and a pinion gear driven by said further rack operating said rotary valve means.
 6. A tool as in claim 5 wherein the axis of the rotary valve means is vertical.
 7. A tool as in claim 1 wherein said valve means is positioned at one end of the bore. 